Slightly faster searching

We noticed that almost everyone adds a "checked off=yes/no" criteria when making a complex search. It makes sense. You're either looking for an active tasks or completed tasks, rarely both at the same time. So, we added the "checked off=no" criteria as a default parameter for new searches. This should make searching for tasks a little quicker. If you don't want this default rule, just click the x to make it go away.